1. Field of the Invention
The present invention relates to a mobile satellite communication system in which a satellite provided with a large-scaled antenna thereon is put in a static orbit or a substantially static orbit so as to carry out communication by means of a plurality of beams.
2. Description of the Related Art
A conventional mobile satellite communication system will be described with reference to FIG. 10. FIG. 10 is a diagram showing a conventional mobile satellite communication system disclosed, for example, in U.S. Pat. No. 5,500,648.
In FIG. 10, reference symbol E denotes the earth and S is an artificial satellite.
The mobile satellite communication system shown in FIG. 10 is designed to perform communication while several tens of satellites S are made to round in a low-round orbit situated at a longitude several hundreds Km above the ground.
The feature of the mobile satellite communication system resides in that a world-wide communication network is produced through the artificial satellites S so that communication can be made from an arbitrary place to a desired place.
Thus, in the above-mentioned conventional mobile satellite communication system, the world-wide communication network is provided. However, there is such a problem that although communication channels must be ensured in specific areas because a demand for communication is recently rapidly increased, the provision of the world-wide network makes it difficult to flexibly cope with an increase in the demand for communication in the specific areas.